Igniter for furnace

ABSTRACT

An igniter includes an insulative body, and a resistive conductor positioned within the insulative body. The insulative body of the igniter can be made of a ceramic. In another embodiment, the insulative body is made from a non water absorbing material.

RELATED APPLICATION

This patent application claims the priority benefit of U.S. Provisional Patent Application Ser. No. 60/868,269, filed Dec. 1, 2006 and entitled “SPEED CONTROL METHOD AND APPARATUS FOR AN ELECTRICAL DEVICE”, which application is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is related to a structure for an igniter for a furnace and methods for using the same.

BACKGROUND OF THE INVENTION

Biomass is one of the oldest fuels known to man. Simply stated, biomass is vegetation or fuel from plants, agricultural waste products or the like. During photosynthesis, plants combine carbon dioxide from the air and water from the ground to form carbohydrates that are the building blocks of biomass. The solar energy that drives photosynthesis is stored in the chemical bonds of the structural components of biomass. Burning biomass efficiently extracts the energy stored in the chemical bonds and produces carbon dioxide and water. Generating energy and heat by burning biomass displaces more polluting forms of energy generation and also provides other environmental benefits, such as reducing acid rain, soil erosion, water pollution and pressure on landfills. Additional environmental benefits include mitigating climate changes, providing wildlife habitat, and helping to maintain forest health through better management.

Biomass fuel is both abundant and renewable. There is biomass in virtually every part of the world that can be tapped to create power. If all the biomass potentially available today were used to produce energy an estimated 2,750 Quads. (1 Quad is equal to 1,000,000,000,000,000 BTUs) would be produced. At present, the world population uses only about 7% of the available annual production of biomass. As a result, biomass is not only the logical alternative fuel of the future but is also currently a logical source of energy.

Stoves or furnaces for burning biomass fuel to produce energy are not new. There are many stoves and furnaces for burning biomass fuel, however, there currently is not widespread acceptance of these furnaces or stoves by consumers. Cost is one of the main motivators leading consumers to use a stove or furnace that burns biomass fuels. However, consumers of current biomass fuel stoves or furnaces many times have to compromise in terms of cleanliness and convenience when switching to a furnace that burns biomass fuels. One main area of inconvenience is starting and running the furnace. Many times the furnace has to be stoked in the middle of the day or the middle of the night. There is also a problem with variable heat output from many furnaces. The furnace produces too much heat during some times and too little heat at other times. In other words, sometimes the heated space is too hot and sometimes the heated space is too cold. At times, for example, a house heated with wood may have its windows wide open during the middle of the winter. At other times, like early in the morning, one brave soul will have to brave the cold, dance across the cold floor and start or restart the stove. Another problem stems from the fact that the furnace may go out inadvertently and fill the heated space with smoke. This is not only messy, but also dangerous. In many furnaces or biomass stoves, the biomass fuel may not be completely burned. This equates to an inefficient use of the biomass fuel. In addition, when the biomass fuel is not completely burned, the waste or ash produced by the biomass furnace or stove is less dense. The less dense the burned or partially burned fuel, the more frequently the stove or furnace must be cleaned.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is pointed out with particularity in the appended claims. However, a more complete understanding of the present invention may be derived by referring to the detailed description when considered in connection with the figures, wherein like reference numbers refer to similar items throughout the figures, and:

FIG. 1 is perspective view a furnace having a combustion chamber with the burn port, according to an example embodiment.

FIG. 2 is an exploded perspective view of a portion of the combustion chamber and the burn pot of the furnace, according to an example embodiment.

FIG. 3 is a top cross-sectional view of a furnace having a combustion chamber with the burn pot, according to an example embodiment.

FIG. 4 is a partially cut away perspective view of the furnace, according to an example embodiment.

FIG. 5 is a schematic view of a biomass furnace and a control system for the biomass furnace, according to an example embodiment.

FIG. 6 is a schematic view of an embodiment of a feeder wheel and motor for driving the feeder wheel, according to an example embodiment.

FIG. 7 is a flow diagram for controlling the feeder wheel, according to an example embodiment.

FIG. 8A is a top view of an embodiment of a feeder wheel within the fuel hopper of a biomass furnace, according to an example embodiment.

FIG. 8B is a back side exploded view of feeder wheel assembly, according to another example embodiment.

FIG. 8C is a top view of ring of the feeder wheel, according to an example embodiment

FIG. 8D is a view of a slot of the ring of the feeder wheel along line 8D-8D in FIG. 8C, according to another example embodiment.

FIG. 8E is a flow diagram of a method, according to an example embodiment

FIG. 9A is a cut-away perspective view of an igniter, according to an example embodiment.

FIG. 9B is a cut-away perspective view of an igniter, according to another example embodiment.

FIG. 10 is flow diagram for controlling a biomass furnace, according to an example embodiment.

FIG. 11 is a flow diagram for controlling the igniter, according to an example embodiment.

FIG. 12 is a flow diagram of a method for controlling the igniter, according to an example embodiment.

FIG. 13 is another flow diagram for controlling the igniter, according to an example embodiment.

FIG. 14 is a flow diagram of a method for igniting fuel when using a plurality of igniters, according to an example embodiment.

FIG. 15 is another flow diagram for controlling the igniter, according to an example embodiment.

FIG. 16 is a stove calibration method, according to an example embodiment.

FIG. 17 is a stove calibration interface, according to an example embodiment.

FIG. 18 is a computer to stove monitor interface, according to an example embodiment.

FIG. 19 is a flow diagram of a method for controlling the air flow, according to an example embodiment.

FIG. 20 shows an apparatus for controlling the power to a device, such as a fan on a furnace, according to an example embodiment.

FIG. 21A is a flow diagram of a method for driving a device, according to an example embodiment.

FIG. 21B is a flow diagram of a method for driving a device, according to an example embodiment.

FIG. 22 is a flow diagram of a method for handling a blocked flue condition, according to an example embodiment.

FIG. 23 is a flow diagram of a method for handling a blocked flue condition, according to an example embodiment.

FIG. 24 is a screen print of a computer-to-stove or furnace interface, according to an example embodiment.

FIG. 25 is a method of receiving and displaying information from a furnace or stove, according to an example embodiment.

FIG. 26 is a schematic diagram of a computer system or controller associated with the biomass furnace, according to an example embodiment.

FIG. 27 is a display for displaying test results from many of the components included in a biomass furnace, according to an example embodiment.

FIG. 28 is a display for displaying the results of diagnostic checks that are conducted during the operation of the furnace, according to an example embodiment.

FIG. 29 is a flow diagram of a method for receiving and displaying a test result value, according to an example embodiment.

The description set out herein illustrates the various embodiments of the invention, and such description is not intended to be construed as limiting in any manner.

DETAILED DESCRIPTION

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention can be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments can be utilized and derived therefrom, such that structural and logical substitutions and changes can be made without departing from the scope of present inventions. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments of the invention is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

FIG. 1 is perspective view a furnace 100 having a combustion chamber 110 with the burn pot 300, according to an embodiment of this invention. The furnace 100 includes a housing 120. The combustion chamber 110 and burn pot 300 are within the housing 120. At least a portion of the burn pot 300 and at least a portion of the combustion chamber 110 a viewable through a window 122. The window 122 is sealed with respect to the housing 120. The housing 120 also includes an access panel 124 that allows access to a portion of the interior of the furnace 100 located below the burn pot 300. The access panel, in some embodiments, allows users to remove combustion products from the furnace 100. The housing 120 also includes a hopper and a feed mechanism (shown in FIG. 4) for controllably placing biomass combustibles into the burn pot 300 in the combustion chamber 110. The housing 120 of the furnace includes a door 126 that allows access to the hopper (not shown in FIG. 4). Biomass fuels are placed into the hopper after opening door 126. Any type of biomass can be used as a fuel. For example, corn, wood chips, or pellets of biomass material are among the fuel sources. The furnace 100 is shown in FIG. 1 in a space heater application. Other applications of the furnace include a forced air furnace, a hot water heater, an electrical generator, a swimming pool heater, or for heating water for circulation within a hot water heating system. Other applications are also contemplated.

FIG. 2 is an exploded perspective view of a portion of the combustion chamber 110 and the burn pot 300 of the furnace 100, according to an embodiment of this invention. The combustion chamber 110 is bounded by a top burner plate assembly 210 and a bottom plate 220. The combustion chamber also includes a back wall 212. Attached to the bottom plate 220 is a first pin 222 and a second pin 224. The burn pot assembly 300 includes a first burn pot portion 310 and a second burn pot portion 320. The first burn pot portion includes a side wall 312. The side wall 312 has openings, such as opening 314 therein, for directing combustion air around the burn pot assembly 300. The second portion of the burn pot 320 also has a side wall 322. The sidewall 322 also includes openings, such as opening 324, for directing air entering from outside the burn pot assembly 300 to within the burn pot assembly. Also attached to the side wall 322 of the second burn pot portion 320 is a mounting wing 326. The mounting wing 326 includes openings that allow the mounting wing 326 to fit over the first pin 222 and the second pin 224 attached to the bottom plate 220 of the combustion chamber 110. Attached to the side wall 312 of the first burn pot portion is another mounting wing 316, which has opening therein so that the mounting wing 316 also fits over the first pin 222 and the second pin 224 of the bottom plate 220 of the combustion chamber 110.

Also located within the combustion chamber is a movable floor 240 and a translating plate 250. The movable floor includes a grill 242 and an opening 244. The movable floor 240 is attached to a pivot pin 245 so that the moving floor 240 can pivot around the pivot pin 245. The translating plate 250 also has an opening 254 therein. The translating plate 250 also includes a solid surface area 252. The translating plate 250 also is pivotally attached to the pivot pin 245. An actuator rod 400 is attached to the movable floor 240 as well as the translating plate 250. The actuator rod 400 is used to move the movable floor 240 and the translating plate 250 between a first position and a second position. In some embodiments, separate actuator rods are used to move the movable floor 240 and the translating plate 250.

Also attached to the burn pot assembly 300, and specifically to the second portion of the burn pot 320, is an igniter 260 and an igniter 262. The igniters 260, 262 place heated air into the burn pot assembly 300. The igniters 260, 262 are in fluid communication with the interior portion of the burn pot assembly. The igniters 260, 262 are used to initially fire the furnace or to initially ignite biomass fuel added to the burn pot assembly 300. Once the biomass fuel within the burn pot has been started, the igniters 260, 262 no longer place heated air into the burn pot assembly 300.

Positioned below the bottom plate 220 is a combustible product tray 270. The combustible product tray 270 includes a floor 272 as well as at least one side wall. Attached to the floor 272 of the combustible product tray 270 is a distributor 274. The distributor 274 is positioned so that when a portion of an ash column is removed from the burn pot assembly 300, the distributor 274 prevents the product from merely stacking up on the floor 274 of the combustible product tray 270. In other words, the distributor 274 distributes the byproduct of combustion from the burn pot over the floor 272 of the combustible product tray 270.

As shown in FIG. 2, the movable floor 240 and the translating plate 250 are in a first position. While in the first position, the grill 242 having openings therein of the movable floor 240, the second portion of the burn pot 320, the opening 254 in the translating plate 250, and the first portion of the burn pot 310 are substantially aligned to form the burn pot assembly 300. When the translating plate 250 and the movable floor 240 are in the first position, the biomass material can be inserted into the burn pot assembly 300 and specifically can drop to the grill portion 242 of the movable floor 240. The igniters 260, 262 are turned on to initially ignite the biomass material. Once the biomass material is burning, additional biomass material is placed through an opening 211 in the top burner plate assembly 210 and into the burn pot assembly 300. Combustion air can be forced through the openings 314 within the first burn pot portion 310 and through the openings 242 in the second burn pot portion 320, respectively, to provide sufficient oxygen for the biomass fuel to burn completely. As burning continues, an ash column 500 (shown in FIGS. 5-7) builds within the burner pot assembly 300. The ash column 500 eventually builds up to a point where the ash column 500 is above the second portion of the burn pot 320, and above the translating plate 250.

FIG. 3 is a top cross sectional view of the furnace 100 and specifically the combustion chamber 110 with the burn pot assembly 300. As shown in FIG. 3, the combustion chamber 110 also includes side walls 213 and 215, as well as a front wall 217. The igniters 260, 262 extend through openings in the side walls 215, 213, respectively. The actuator rod 400 is moved by an actuator motor 410. The combustion chamber 110 also includes a forced air inlet 390. The actuator rod 400 is covered by a bellows 402, as well as a housing 404 attached to the back wall 212 of the combustion chamber 110. As shown in FIGS. 2 and 3, the ends of the movable floor 240 and the translating plate 250 extend through an opening in the back wall 212. The actuator motor 410 and the actuator rod 400 are used to move the translating plate 250 and the movable floor 240 between a first position and a second position. As shown in FIG. 3, the translating plate 250 and the movable floor 240 are in a first position where the grill 242, the second portion of the burn pot 320, the opening 254 within the translating plate 250, and the first portion of the burn pot 310, are substantially aligned with the opening 211 in the top burner assembly.

FIG. 4 is a partially cutaway perspective view of the furnace 100, according to an example embodiment. The furnace includes a housing 120 and includes a hopper 420 which holds fuel 426. Positioned within the hopper is a feed mechanism 430 which is attached to a motor 432. The feed mechanism 430 can be termed as a feeder wheel which has slots therein. A portion of the fuel 426 falls within the slots while the motor 432 turns the feeder wheel to move the fuel in the slots from the lower portion of the hopper to a feeder tube 440. The feeder tube is a tube that connects the hopper 420 to the combustion chamber 110. Specifically the feeder tube 440 is positioned so that the fuel within a slot drops through the feed tube 440 and into the burn pot assembly 300 within the combustion chamber 110. The rate at which the fuel is input to the combustion chamber and specifically to the burn pot mechanism 300 can then be controlled by controlling the motor 432 which rotates or turns the feeder mechanism or feeder wheel 430. The furnace or stove 100 also includes a controller 500 which controls many aspects of the stove or furnace. The controller 500, for example, controls the rate at which fuel is input into the burn pot 300.

The furnace 100 also includes a heat exchanger 450. The heat exchanger 450 removes additional heat from the exhaust gasses near the combustion chamber to extract additional heat from the exhaust gasses of the combustion process. The furnace 100 also includes a combustible product tray 270 which holds the pucks or other ashes after they have been substantially burned. The combustible product tray 270 can also be referred to as an ash drawer. The user of the furnace 100 can remove the combustion products or ashes from the ash drawer 270. The furnace also includes a dynamic air system 460, as well as a flue 470 and a sensor 472 within the flue. An additional sensor 474 is also located within the flue for measuring the flow rate of gasses through the flue. The furnace 100 also includes an air inlet or intake 490. Located within the air inlet or intake 490 is another sensor 492. The sensor 492 can be a thermal couple and can be used to measure temperature of the ambient air pulled into the furnace 100. The ambient air is combusted in the furnace 100. This further increases efficiency since already warmed air is not used in the combustion process.

FIG. 5 is a schematic view of a biomass furnace and the control system 500 for the biomass furnace, according to an example embodiment. The controller 500 controls an ignition control module 510, a feeder wheel control module 520, an airflow control module 530, a furnaced monitor module 540, a flue block module 550, and an ash dump and timing module 560. Each of the individual modules 510 can be software or can be hardware or a combination of both. As shown in FIG. 5, the various modules 510, 520, 530, 540, 550 are positioned within the furnace 100. If they are hardware, they are more than likely positioned within the furnace or within a portion of the furnace. If they are software, they are more than likely positioned so that they interface with the furnace and they are not necessarily in the furnace but may be part of the controller, such as a microprocessor. Suffice it to say that the controller 500 controls many aspects of the furnace including ignition control, control of the feeder wheel, control of the airflow, control of a monitoring function as well as a detection of a blocked flue and how to handle a blocked flue when detected.

FIG. 6 is a schematic view of an embodiment of a feeder wheel and the motor for driving the feeder wheel, according to an example embodiment. FIG. 6 shows the feeder wheel 630 and the electric motor that drives the feeder wheel 632 outside of the hopper 420 for the sake of clarity. The feeder wheel 630 includes a number of slots 640, 641, 642, 643, and so on. In actuality there are more slots than slots 640, 641, 642, 643 but all these slots are similarly shaped and positioned at substantially equalized spaced positions about the periphery of the feeder wheel 630. Also shown in FIG. 6 is a feeder tube 440. The feeder tube 440 has an opening 441 positioned near the feeder wheel 630. The opening 441 is generally larger than the individual slot 640, 641, 642, 643. The opening 441 corresponds to an opening in the hopper. Therefore, in operation the feeder wheel 630 turns and passes through the bottom of the hopper and fuel falls into the individual slots, such as slot 640, 641, 642 and 643. The feeder wheel is rotated to a position where a particular slot is positioned over the opening in both the hopper 420 and the feeder tube and the opening 441 and the feeder tube 440. When the slot is positioned over the openings, the fuel that is within the slot, such as slot 643, is dropped through the tube and into the burn pot assembly 300 (as shown in FIG. 4). The controller 500 acts through the feeder wheel control module 520 to control the electric motor 632 and the feeder wheel 630 attached to the electric motor via an electric motor shaft 650.

FIG. 7 shows a flow diagram for controlling the feeder wheel 630 according to an example embodiment. The feeder wheel control method 700 includes a determination of time between each movement of the feeder wheel. In this particular embodiment, the feeder wheel moves through a specific arcuate path and then stops periodically. The initial step is to enable the fuel feed wheel 710, then to move the slot in the fuel feed wheel into alignment with the fuel feed tube 712 and then to disable the fuel feed motor 714. Next comes a decision as to whether the time as elapsed between fuel feed wheel movements. If the time has not elapsed between the fuel feed movements, the fuel feed motor remains disabled. If the time between the fuel feed wheel movements has elapsed, the fuel feed motor is re-enabled 710, and the sequence is repeated. The controller 500 determines a rate at which fuel needs to be burned in order to produce a quantity of heat selected. This, in turn, is used to determine a time between the fuel feed wheel movements. In another embodiment of the invention, the feed wheel 630, 430 is turned substantially continuously. The rate of fuel feed into the burn pot assembly 300 is then determined by the rate at which the feed wheel is turned.

FIG. 8A shows a fuel feeder wheel 830 having slots 840, 841, 842, 843. The slots 840, 841, 842, 843 are non-radially positioned or are transverse to a radial line associated with the feed wheel 830. In this particular way, the fuel is feed more gradually into the feed tube. Since the slots 840, 841, 842, 843 are transverse to a radial of the feed wheel, the feed enters the feed tube gradually as the fuel at the top of the slot is first place over the opening corresponding to the feed tube. As the feed wheel continues to rotate, additional volume of the slot is moved or placed over the opening corresponding the opening of the feeder tube.

FIG. 8B is a back side exploded view of feeder wheel assembly, according to an example embodiment. The feeder wheel assembly 810 includes a feeder wheel 831 having slots 844, 845, 846 and 847. The feeder wheel 831, in this embodiment, includes center plate 832 and an outer ring 833. The outer ring 833 includes the slots 844, 845, 846 and 847. The feeder wheel 831 rides on a feeder plate 850. The feeder plate 850 is mounted to a portion of a fuel hopper 420 or fuel bin which holds the solid bio fuel (shown in FIG. 4). The feeder wheel assembly also includes a motor 860 which is capable of being driven backwards when not powered or driven by electrical power. One such motor is available from SPG Co., Ltd located at 67B/112LOT, 628-11, Gojan-Dong, NamDong-Gu, Korea as part number ISG-3220BXA. The motor 860 is attached to the feeder plate 850 through a damper apparatus capable of absorbing energy from the motor 860 when and if the feeder wheel 831 becomes immobile when something, such as some of the solid bio fuel, is stuck in one of the slots 844, 845, 846, or 847 of the feeder wheel 831 and the opening in the feeder plate 850. The opening in the feeder plate 852 is shown in phantom in FIG. 8B since is covered by feeder tube 854 which is attached to the feeder plate. The feeder plate 850 is stationary and attached to the inside of the fuel hopper 420 or fuel bin in the stove. The feeder wheel assembly 810 also includes a damper plate mount 862. The damper plate mount 862 includes one or more dampers, such as damper 864. In one example embodiment, the motor 860 is indirectly attached to the feeder wheel 831 through a damper. The damper plate mount or the damper must be sufficiently inelastic to deliver torque to spin the feeder wheel 831 through fuel and over the feeder plate 850. The damper plate mount or damper must also be sufficiently elastic to yield and store energy when the feeder wheel 831 becomes immobilized or stuck. The damper plate mount or damper must also be capable of storing a sufficient amount of energy to spin the shaft 861 of the motor 860 in an opposite (or second) direction when the power to drive the shaft 861 of the motor 860 for moving the drive shaft 861 in a first direction is disabled or removed. The torque needed to move the shaft 861 of the motor 860 in the second direction must be low enough so that the energy stored in the damper or dampers can spin the drive shaft 861. In other words, the dampeners must be matched or paired with the motor 860. A spring 855 and a washer 856 fit over the feeder tube 854. The spring 855 and washer 852 allow a portion of the feeder tube attached to the combustion chamber 110 to float as the combustion chamber 110 heats and cools when fuel is being burned and heat is being produced. A solid connection between the combustion chamber 110 and the fuel bin 420 or hopper would fail due to thermal expansion at the combustion chamber and no corresponding expansion at the fuel bin or hopper 420.

FIG. 8C is a top view of ring 833 of the feeder wheel 831, according to an example embodiment. The ring 833 of the feeder wheel 831 includes the slots 844, 845, 846, or 847. The slots 844, 845, 846, or 847 form sidewalls. Some of the side walls are beveled or angled with respect to one of a first major surface 836 or a second major surface of the ring 833 of the feeder wheel 831.

FIG. 8D is a view of a slot 845 of the ring 833 of the feeder wheel 831 along line 8D-8D in FIG. 8C, according to an example embodiment. A line normal to the first major surface 836 or the second major surface 837 is shown as 838 in FIG. 8D. The sidewall 848 and the sidewall 849 make an angle (beta) with respect to the normal 838. The angle beta in one embodiment is approximately 20 degrees. In other embodiments, the angle beta is in the range of 10 degrees to 30 degrees. The angle is sufficient to form a cutting edge along the sidewall of the slot 845. In this way, if fuel or some other object obstructs or jams the feeder wheel 831, the edge formed may be able to cut the object to free the feeder wheel 831.

The feed mechanism includes a high ratio AC gear motor that drives the thin slotted feeder wheel 831. One advance of the feeder wheel 831 drops a nearly fixed volume of fuel into the fire box or combustion chamber 110 of the stove 100. The high ratio AC gear motor is mounted to one side of the feeder plate 850 via damper system or mechanism. The feeder wheel 831 is in contact with the other side of the plate 850. The damper system or mechanism serves two purposes: reduction of sound and vibration, and as an energy storage device for, in some instances, reversing the motor when it is not being powered.

In operation, a normal feed advance, the torque load necessary to move the fuel feeder wheel 831 is relatively low. The high ratio AC gear motor 860 is operated well below its stall range, and the dampers or dampening mechanism 862 serve to reduce sound. If fuel becomes lodged between the feeder wheel 831 and the feeder plate 850, the feeder wheel 831 becomes stationary relative to the stove. However, the high ratio AC gear motor 860 is able to keep operating for some time after the feeder wheel 831 stops since the rubber dampers deform and allow the motor 860 to continue to rotate through a distance until the gear motor 860 reaches its stall torque. In this case, the AC motor 860 will maintain the displacement of the dampers as long as power is applied. Energy is stored in the dampers or damping mechanism 862. The amount of energy stored in the dampers is proportional to their stiffness times the amount of displacement of the dampers. When power is removed from the AC gear motor 860, the force necessary to maintain the displacement of the dampers is also removed. When power is removed from the AC gear motor 860, the energy stored in the dampers 864 is released as a torque in the opposite or reverse direction of the drive shaft 861 of the regular operation of the AC motor 860. The energy stored in the dampers is applied between the gear motor frame 860 and the back mounting plate 850. Note that, due to the jammed bio fuel, such as a pellet, the frame of reference of the back mounting plate is the same as the jammed feeder wheel.

The torque from the dampers in the reverse direction of the normal torque, back drives the gear motor mechanism and drive shaft 861 of the motor 860 and makes the drive shaft 861 spin in the reverse direction. As the gear motor spins, it draws energy from the dampers, which is the manifestation of a reduction of displacement. At approximately the point where the damper mechanism 862 has released all its energy, the gear motor 860 is spinning in the opposite direction at approximately maximum speed and the feeder wheel 831 is still jammed. The energy (less some mechanical loss) that was stored in the dampers is now in stored in the rotating mass of the gear motor rotor. The gear motor continues spinning, and now produces another force in the rubber dampers in the opposite direction of their original displacement. This provides the force necessary to turn the feeder wheel 831 in the opposite or reverse direction from the normal operation. When the feeder wheel 831 moves backwards or rotates in the opposite direction from normal, the solid biomass fuel that caused the jam may dislodge thereby freeing the feeder wheel 831. Eventually the kinetic energy associated with the rotating or spinning gear motor is disappated, and the feeder wheel 831 substantially stops. At the next time when the feeder wheel 831 is powered or enabled to rotate and place additional fuel into the combustion chamber, if the jam was clear, the system will work without reversing.

A stove 100 for heating with solid bio fuels includes a combustion chamber 110, a fuel bin 420 that includes a wall having plate 850 with an opening 852 therein, and a feeder wheel 830, 831 rotatably mounted on a side of the plate inside the fuel bin 420. The feeder wheel has slots 844, 845, 846 and 847, therein for carrying a portion of solid fuel. The stove 100 also includes a damper apparatus 862, and a motor 860 mounted on the outside of the fuel bin 420. The motor 860 includes a drive shaft 861. The motor 861 is mounted to drive the feeder wheel 830, 831 and the damper apparatus 862. The damper apparatus 862 absorbs at least some rotational energy when the feeder wheel 830, 831 rotation is stopped as the motor 860 continues to apply a torque to the feeder wheel 831. The damper 862 is capable of rotating the drive shaft 861 with the energy stored in the damper apparatus 862. The stove 110 also includes a feeder tube 854 positioned near the opening 852 in the plate 850. The feeder tube 852 receives solid fuel from the feeder wheel 83 land delivers the solid fuel to the combustion chamber 110. The stove 100 also includes a switch for applying power to the motor 860 for a selected amount of time and removing power for a selected amount of time. In some embodiments, the stove 100 includes a feeder wheel control module 520 for controlling the time when power is delivered to the electrical motor 860 of the feeder wheel 830, 831. The feeder wheel 831 includes a first major surface 836 and a second major surface 837. The slots 844, 845, 846 and 847, in the feeder wheel 831 are formed between the first major surface 836 and the second major surface 837. The slot forms sidewalls 848, 849 and at least one of the sidewalls forms an angle (beta) with respect to a normal 838 to one of the first major surface 836 or the second major surface 837. The edge formed by the side wall, in some embodiments, is adapted to cleave a material caught between a sidewall and the opening 845 in the feeder wheel 831. A feed apparatus includes a fuel bin that includes a wall having plate with an opening therein, and a feeder wheel rotatably mounted on a side of the plate inside the fuel bin. The feeder wheel has slots therein for carrying a portion of fuel. The feed apparatus also includes a damper apparatus, and a motor mounted on the outside of the fuel bin. The motor includes a drive shaft. The motor is mounted to drive the feeder wheel and the damper apparatus. The damper apparatus absorbs at least some rotational energy when the feeder wheel rotation is stopped as the motor is applying a torque to the feeder wheel, and the damper is capable of rotating the drive shaft with the energy stored in the damper apparatus. The feeder wheel also includes a first major surface, and a second major surface. The slots in the feeder wheel extend between the first major surface and the second major surface. The slots form sidewalls in the feeder wheel. At least one of the side walls makes an angle with respect to a normal to one of the first or second major surfaces. The angle associated with the at least one of the side walls is in a range of 10 degrees to 30 degrees with respect to the normal to one of the first or second major surfaces. In one embodiment, the sidewall with the angle trails the other sidewalls when the motor is rotating the feeder wheel. In another embodiment, at least two side walls are formed to make an angle with respect to the first or second major surface.

The damper apparatus has a damping characteristic that allows the motor to displace when the feeder wheel is obstructed, but which is sufficiently rigid to prevent the motor from moving to a starting position. In one embodiment, the damper apparatus includes a damper plate. In another embodiment, the damper apparatus includes a first damper plate attached to a first side of a damper, the first damper plate attached to the motor, and a second damper plate attached to a second side of a damper, the second damper plate attached to the feeder wheel. The damper apparatus includes at least one damper. In another embodiment, the damper apparatus includes a plurality of dampers. The feeder wheel is positioned at a distance from the plate that is less than the smallest dimension of the solid bio fuel.

FIG. 8E is a flow diagram of a method 890, according to an example embodiment. The method 890 includes storing energy produced by an electrical motor in a damper apparatus 892, removing power from the electrical motor 894, and rotating a drive shaft of the electrical motor with energy the stored in the damper apparatus 896. Storing the energy produced by the electrical motor 892 includes driving the drive shaft in a first direction. Rotating the shaft of the electrical motor with the stored energy 896 includes driving the drive shaft in a second direction. After driving the drive shaft in the second direction, the shaft of the electrical motor is driven again in the first direction. In other words, after the stored energy has been dissipated, the drive shaft is driven again in the first direction.

FIG. 9A is a cutaway perspective view of an igniter 900, according to an example embodiment. The igniter 900 includes an elongated portion 902 and a plenum portion or box end 904. Ambient air is input through a tube 914 into the plenum or box 904. The tubular portion 902 includes an air passageway 912 along the length of the tubular portion 902. Ambient air is thus input into the tube 914 into the plenum 904, then the passes through the length of the tubular portion and exits out an end of the tube 914. As shown in FIG. 9A, the elongated portion 902 includes a rod 920. A resistive element 910 is wrapped around the rod 920. The ambient air from the plenum or box end 904 is then passed over the resistive element as it passes through the air passageway 912 and is heated along the distance of the tubular element. The heated air is then output from the end 914 of the igniter 900. As shown in FIG. 9A, the tubular element 902 is made of a non-conductive ceramic or non-porous material. In one embodiment, the tubular element 902 is made from a non-water absorbing material. The rod 920 is also made of a non-conductive ceramic or non-porous, non-water absorbing material. These materials prevent or substantially lessen the possibility of shorts occurring along the length of the resistive element 910 due to water condensation being absorbed into the material and then escaping the material as the igniter 900 cools and shorting out the resistive element 910.

FIG. 9B shows another embodiment of an igniter 950. The igniter 950 includes a elongated portion 952 and a plenum or box end 954. The plenum is attached to an air inlet 964 or a tube that passes ambient air into the box end. The tubular portion includes openings which run the length of the tubular portion. As illustrated in FIG. 9B, the elongated end is partially cutaway to expose openings 970 and 972. Other openings are also elongated or substantially parallel to the axis of the tubular portion 952 and include openings 973, 974 and 975. A resistive element 960 is threaded through the openings such as 970 and 972 as well as the other openings 973, 974 and 975. Air is then passed from the plenum or box end 954 and passed through the elongated openings or elongated passageways which are substantially parallel with the axis of the tubular end 952. As the air passes through the elongated openings 970, 972, 973, 974, 975 the air is passed by or over the resistive elements 960 within the openings. As a result, the air heats up as it passes through the elongated openings 970, 972, 973, 974, 975 from the plenum or box end 954 to the outlet end or free end of the igniter 950. At the plenum or box end 904, the air is at ambient temperature (the temperature of the outside air as input into the furnace or stove). The elongated or tubular portion 952 is made of a non-conductive ceramic or other non-porous, non-water absorbing material so as to lessen the chance of a short in the resistive element 960. Thus, in the embodiment shown, the insulative portion substantially surrounds the resistive element that heats the air. Of course in each of the embodiments of FIGS. 9A and 9B there is power input to the resistive element 910, 960, as depicted by two input wires which go into the box end 904, 954 and carry the reference numerals 930 and 980, respectively.

Thus, the igniter 900, 950 includes an insulative body 902, 952, and a resistive conductor 910, 960 positioned within the insulative body 902, 952. The insulative body 902, 952 of the igniter can be made of a ceramic. In another embodiment, the insulative body 902, 952 is made from a non water absorbing material. The insulative body 902, 952, in some embodiments, includes a tubular portion. In some embodiments, the insulative body is a cylinder of substantially non water absorbing material. The insulative body can include a tubular portion 902 with the cylinder or rod 920 of substantially non water absorbing material positioned within the tubular portion 902. The tubular portion 902 can be made of a substantially non water absorbing material. The resistive conductor 910 is positioned substantially around the cylinder or rod 920. The resistive conductor is positioned substantially within the cylinder.

A system includes a combustion chamber 110, a burn pot 300 within the combustion chamber 110, and at least one igniter 910, 950 positioned to ignite fuel within the burn pot 300. The at least one igniter 910, 950 further includes an insulative body 902, 952, and a resistive conductor 910, 960 positioned within the insulative body 902, 952. The insulative body 902, 952 of the igniter 900, 950 is made of a ceramic or a non water absorbing material. In some embodiments, the insulative body 902, 952 of the igniter includes a tubular portion 902. In other embodiments, the insulative body of the igniter includes a cylinder 920 of substantially non water absorbing material. The cylinder 920 of substantially non water absorbing material positioned within the tubular portion 902. The tubular portion 902, in some embodiments, is made of a substantially non water absorbing material. The resistive conductor 910 of the igniter 900 is positioned substantially around the cylinder 920 of the igniter 900. In another embodiment, the resistive conductor 960 of the igniter 950 is positioned substantially within the cylinder 952. In some embodiments, the resistive conductor 910 of the igniter is positioned around the cylinder 920 of the igniter 900. In still other embodiments, the system includes a controller 500 (shown in FIGS. 4 and 5) for controlling the at least one igniter 900, 950.

The igniters and portions of the furnace or stove can be part of a system 100. The system 100 includes a combustion chamber 110, a burn pot 300 within the combustion chamber 110, a first igniter 900, 950 positioned to ignite fuel within the burn pot, and a second igniter 900, 950 positioned to ignite fuel within the burn pot. The at least one of the first igniter 900, 950 or the second igniter 900, 950 further includes an insulative body 902, 952, and a resistive conductor 910, 960 positioned within the insulative body 902, 952. The system further includes a controller for controlling the at least one igniter. The system, in some embodiments, also includes a back up device for igniting the fuel within the burn pot 300.

FIG. 10 is a flow diagram for controlling a biomass furnace, according to an example embodiment. The controller 500 (shown in FIG. 5) controls many aspects of the stove or furnace 100. As mentioned in FIG. 5, the controller controls an ignition control module 510, a feeder wheel control module 520, an airflow control module 530, a furnace monitor module 540, and a flue block module 550. Each of the individual modules 510, 520, 530, 540, 550 can be in part hardware or in part software or can be a combination of both hardware and software. The controllers are used to control certain portions of the stove or furnace 100. Of course, even though certain control modules are discussed herein it should be noted that a system can have other control modules for controlling other aspects of the stove or furnace 100. Of course, it should also be understood that, in some example embodiments, the controller does use or have all the control modules discussed in this specification. Initially, the controller 500 that controls all or part of the control modules, determines a set of control values, as depicted by reference numeral 1010. In other words, certain parameters are measured or specified about the stove and in the environment under which it operates. The operator also selects a desired heat output for the stove. Between the parameters of the stove and the desired heat output as well as other factors, a set of control values is determined by the controller, as depicted by reference numeral 1010. The stove can then be controlled in various sequences. In one embodiment, such as the example embodiment shown in FIG. 10, the stove is ignited, as depicted by reference numeral 1012 and the amount of fuel input into the combustion chamber and the burn pot is controlled, as depicted by reference numeral 1014. The airflow is also controlled, as depicted by reference numeral 1016, and the stove is monitored while the fuel is burning in the burn pot and while the stove is producing heat, as depicted by reference numeral 1018. Various conditions are monitored, one of which is determined whether or not a flue or exhaust pipe from the stove is blocked, as depicted by reference numeral 1020. If the flue is not blocked or there is no indication of a blocked flue condition, the operation of the stove is continued, as depicted by reference numeral 1022. If the flue is blocked, a certain procedure is set in place to stop the stove or furnace, as depicted by reference numeral 1024. Of course, the operator can also choose to end the operation of the stove and command the stove to cease operating.

FIG. 11 is a flow diagram for controlling the igniter according to an example embodiment. The flow diagram could be associated or as one of the methods associated within ignition control module 510 (shown in FIG. 5). A signal is received for starting the ignition of the fuel, as depicted by reference numeral 1110. Ambient air temperature is then measured outside of the furnace or stove, as depicted by reference numeral 1112. The ambient air temperature is the temperature of the combustion gas or the air that is used in the burning process. Typically outside air will be used in the furnace so that air that has already been heated by the furnace is not wasted in the combustion process. Also when initially combusting the fuel, the current that is passing through the igniter is also measured, as depicted by reference numeral 1114. The current measure 1114 gives an indication of how much heat is being placed into the air and will also allow for an accurate estimate of the air temperature at the output end of the igniter 900, 950 (shown in FIGS. 9A and 9B). Based on the ambient air temperature, the igniter current, and the fuel type being used in the burn pot of the combustion chamber 110, a base igniter on time is calculated or determined, as depicted by reference numeral 1116. A base time for the igniter depends upon the type of fuel that is being burned or combusted in the combustion chamber or burn pot. An additional igniter time is added based upon the ambient temperature of the air being used for the combustion process, as depicted by reference numeral 1118. These two values are combined to come up with a total amount of ignition on time through which the igniter or igniters must stay on in order to fully combust or fully start the combustion process. The next step is to turn on the igniters, as depicted by reference numeral 120. In some embodiments, there are more than one igniter. In other embodiments, there is a single igniter. A first decision box includes a determination of whether the ignition threshold has been detected, as depicted by reference numeral 1122. The ignition threshold is the amount of burn or the burn state associated with the fuel in the combustion chamber or burn pot. If the base time has not been exceeded, then, even if an ignition threshold has been detected, the igniter stays on, as depicted by reference numeral 124. If the ignition threshold is detected, then another decision is made, as depicted by reference numeral 126 as to whether the additional on time for the igniter or igniters is exceeded, as depicted by reference numeral 124. If that additional on time has not been exceeded then the igniters stay on until the additional on time has been exceeded. If the additional igniter on time has been exceeded as well as the threshold or the base time has also been exceeded, then the igniters or igniter is turned off as depicted by reference numeral 128, and ignition is either complete or will not happen for some reason (such as absence of fuel), as depicted by reference numeral 130.

The controller 500 contains various interfaces to the igniters or igniter 950, 900 and to a temperature measuring device. The amount of power available to the igniter device and the amount of power that the fuel requires to become satisfactorily ignited or both variable. The power availability and requirements change with the power voltage, the exhaust gas temperature, the ambient temperature of the air, and the fuel characteristics as well as other factors. The extent that the igniter 900, 950 or igniters are able to start the stove or furnace, there are three general states that the stove can ignite the fuel to. In the first state, the fuel is insufficiently ignited. In this case, the fuel may have achieved a burning condition but it is not complete enough to sustain the flame and the fire in the stove or the fire associated with the burning fuel in the burn pot is not self-sustaining and will eventually weaken and go out. Another condition is an excessively ignited condition where the fuel has achieved a burning condition, but the fuel has been burned excessively and there may not be a sufficient amount of fuel in the burn pot so that by adding fuel the added fuel will reliably ignite. The fuel can also be properly ignited such that the fuel is burning well enough to sustain the flame while not already having consumed so much fuel that it will burn out when additional fuel is added. The igniter device is typically operated until ignition is detected at which point the igniter will run for an additional amount of time until it is turned off. Therefore, when an ignition threshold is detected, the exhaust temperature of the gasses will raise thereby indicated that the initial ignition has taken place. The additional time on is added so as to put the fuel into a properly ignited state.

FIG. 12 is a flow diagram of a method 1200 for controlling an igniter, according to another example embodiment. The method 1200 includes determining if an ignition threshold has been achieved for the fuel in the burn pot, as depicted by reference numeral 1210, and then adjusting the amount of time the igniter is enabled to achieve a properly ignited state, as represented by reference numeral 1212.

FIG. 13 is also a flow diagram of a method for controlling an igniter, according to an example embodiment. The method 1300 includes determining an ignition state for a fuel in the burn pot, as depicted by reference numeral 1310, and then changing the state of the igniter in response to a determined ignition state, as depicted by the reference numeral 1312. For example, if the ignition state is a state of properly ignited then the change in state of the igniter is to turn off the igniters. In another instance, if the ignition state is insufficiently ignited then a change in the igniter state might be to extend the length of time that the igniters are on to achieve sufficient ignition.

A system includes a combustion chamber 110 and a burn pot 300. The burn pot 300 is within the combustion chamber 110. The burn pot 300 further includes a sidewall 312, and a movable floor 240 (see FIG. 2). An igniter 950, 900 extends into the burn pot 300. The system further includes an exhaust gas pathway 470 in fluid communication with the combustion chamber 110 (see FIG. 4). The system also includes a temperature sensor 422 associated with the exhaust gas pathway. The system further includes a fuel type designation device. Some embodiments of the system further include a controller or processor 500 having instructions for causing the processor to perform a method of determining an ignition state for the fuel in the burn pot 1310, and changing the state of the igniter in response to the determined ignition state 1312. In another embodiment, the system a processor having instructions for causing the processor to perform a method of determining an ignition state of insufficiently ignited for the fuel in the burn pot, and adjusting the amount of time the igniter is enabled to achieve a properly ignited state 1312 (as shown in FIG. 13).

In still another embodiment, the system includes a processor having instructions for causing the processor to perform a method of determining an ignition state of excessively ignited for the fuel in the burn pot, and adjusting the amount of time the igniter is enabled to achieve a properly ignited state. The system can also include a sensor 492 (see FIG. 4) for measuring the ambient temperature of air input to the combustion chamber, and a processor 500 having instructions for causing the processor to perform a method comprising adjusting the time the igniter is enabled 1212 (see FIG. 12) in response to the measured ambient temperature of the air input to the combustion chamber. The system, in some embodiments, also includes a second igniter, and a processor having instructions for causing the processor to perform a method of determining of one of the igniters is non-operational, and adjusting the length of time the operational igniter is enabled.

In some other embodiments, the system includes a second igniter, and a processor having instructions for causing the processor to perform a method 1400, according to an example embodiment. The method 1400 includes determining of both of the igniters are non-operational 1410, and switching to an alternative process for igniting the fuel 1412.

FIG. 15 is a flow diagram of a method 1500 of controlling ignition, according to an example embodiment. The method includes determining a set of parameters, such as a set of default parameters, for igniting fuel in a combustion chamber of a biomass furnace 1510, selecting a fuel type from a plurality of fuel types 1512, the selected fuel type to be ignited in the combustion chamber, and varying at least some of the plurality of default parameters in response to the selected fuel type 1514. Determining a set of parameters 1510 includes setting a maximum time an igniter for igniting fuel will be enabled, setting a rate at which fuel is fed into a burn pot within a combustion chamber of the biomass furnace, and setting a rate at which a fan will move air through a combustion chamber of the biomass furnace. In some embodiments, the method 1500 also includes determining a temperature of ambient air entering the biomass furnace 1516, and changing the length of time the igniter is enabled in response to a determined ambient air temperature 1518. In some embodiments, the method 1500 also includes shutting down the igniter when the maximum igniter time is reached 1520.

A computer readable medium has instructions for causing a computer to perform a method that includes selecting a fuel type from a plurality of fuel types 1512, the selected fuel type to be ignited in a combustion chamber, and varying at least some of a set of default ignition parameters in response to the selected fuel type 1514. The computer readable medium, in some embodiments, the instructions for causing a computer to perform a method include measuring the temperature of ambient air being input to the combustion chamber 1516, and varying an amount of time an igniter for igniting the fuel is enabled based on the measured temperature of the ambient air 1518. In still other embodiments, the computer readable medium includes instructions for causing a computer to perform a method wherein varying at least some of the parameters includes setting a percentage of a maximum based on the selected fuel type.

In some embodiments, the system has a processor 500 having instructions for causing the processor to perform a method 1500 of igniting a fuel in the burn pot by applying a set of default parameters, and altering the default parameters based on a fuel type and on a temperature of ambient air brought into the combustion chamber. The default parameters can include a maximum igniter time and a maximum startup time.

FIG. 16 is a stove calibration method 1600, according to an example embodiment. The method 1600 includes selecting one of a plurality of types of fuels for a stove 1610, selecting a characteristic associated with the stove 1612, and generating a set of control values in response to the selected type of fuel and the characteristic of the stove 1614. The generating a set of control values may include a first set of control values associated with a heat output of a first level and a second set of control values associated with a heat output of a second value.

FIG. 17 is a stove calibration method 1700, according to another example embodiment. The method 1700 includes selecting one of a plurality of types of fuel for a stove 1710, and selecting a characteristic associated with the stove, as depicted by reference numeral 1712. A first set of control value is generated in response to the selected type of fuel and the characteristics of the stove to produce a first level of heat output, as depicted by reference numeral 1714. A second set of control values is generated in response to the selected type of fuel and characteristics of the stove to produce a second level of heat output, as depicted by reference numeral 1716. The first level of heat output control information is displayed, as depicted by reference numeral 1718, and a second set of stove control information for the second level of heat output from the stove is also displayed, as depicted by reference numeral 1720. In some embodiments of the invention, a selection or designation of either the first level or the second level of heat is made, as depicted by reference numeral 1722.

FIG. 18 is a computer-to-stove monitor interface 1800, according to an example embodiment. The controller in the stove or furnace contains interface to connect with the computer or the controller. The controller executes software or an instruction set that can transmit and receive data that characterizes the stove and the selected fuels and generates a data or control data for the stove controller. The control data defines how the stove or furnace operates or is controlled. Generally the calibration or control data is generated using a number of data tables that are mathematically combined based on a configuration of the stove. This allows multiple stove models and variations to operate using the same controller 500 (shown in FIGS. 4 and 5) and a universal interface software. The interface includes area for selecting several parameters of the stove, as depicted by the type of stove 1811, where the stove is located with respect to altitude, as depicted by 1812, whether the stove has a high output fan or a regular fan, as depicted by reference numeral 1813, and whether the stove is machined or cast, as depicted by reference numeral 1814. These various parameters can be changed, of course, but are parameters that are necessary to the operation of the stove or furnace. In addition to the stove parameters, there is an area for selecting a type of fuel, as depicted by reference numeral 1820. The type of fuel that can be selected (as shown in FIG. 18) is between corn or wood. It should be noted that the fuel selection can include other types of fuel, or other types of biomass material. In addition, a mixture of several forms of fuel can also be selected. For example, there may be a percentage of wood pellets that are mixed with corn to produce a fuel. Again, other types of biomass can be designated as part of the mixture. The biomass is not limited to just corn or wood, but other types of biomass can also be used and mixed. There is also a window or portion 1822 that shows which fuel is actually selected. For the selected fuel there are various levels, as depicted by an L1 level or an L2 level. The L1, L2, . . . L8 levels are shown or depicted as 1830 with respect to fuel A data and 1840 with respect to fuel B data. The levels for L1 have a fan speed, a fuel rate or feed speed, as well as the ash and that occurs for each type of fuel. Of course, only eight levels or shown but further gradations or further levels can be generated. The control values are also generated for each of the type of fuels and parameters selected. Some of the control values vary as depicted by the level areas. Some of the control values are fixed based upon the fuel parameters. These fixed control levels are shown in areas 1840 for fuel A and in area 1850 for fuel B.

The PC-to-stove calibration interface generally performs a method such as the method 1600 and the method 1700 discussed with respect to FIGS. 16 and 17. The computer system, then, includes a graphical user interface including a display and a selection device, a method includes receiving a stove parameter menu entry selection, receiving a fuel designation menu entry selection, and displaying the stove control information. The method of the computer system further comprises generating stove control information in response to the stove parameter menu entry selection and the fuel designation menu entry selection. Displaying the stove control information includes displaying a first set of stove control information associated with a first level of heat output from the stove and displaying a second set of stove control information associated with a second level of heat output from the stove. The method further includes receiving a menu entry selection designating one of the first level of heat or the second level of heat, designating one of the first level of heat or the second level of heat. Receiving a stove parameter menu entry selection includes receiving a selection on the size of the stove, or receiving a model type of the stove. A stove characteristic may be received in response to the model type. The method further includes generating stove control information in response to model type of the stove. The method further includes displaying stove control information. In one embodiment, the method further includes receiving an altitude parameter menu entry selection. Receiving a fuel designation menu entry selection can include a default fuel designation menu selection. In some embodiments, receiving a fuel designation menu entry selection can include receiving a fuel designation menu selection that includes a mixture of fuels.

FIG. 19 is flow diagram of a method 1900 for controlling the air flow into the furnace or stove, according to an example embodiment. As seen in FIG. 18, the exhaust fan or fan speed is controlled or is one of the variable control parameters that is controlled by the controller 500. This can also be seen in FIG. 5 where the controller 500 includes an airflow control module 530. Now turning to FIG. 19, the controller 500 acts through the airflow control module 530 (shown in FIG. 5) to change the speed of the fan and therefore the rate of flow of air associated with the fan. The rate of flow of air will be higher, generally, with higher fan speeds. The only time when the fan speed elevates without a corresponding increase in the flow of air is when a terminal air flow is reached or when a duct is blocked so that no airflow can occur. The airflow control module 530 implements the method 1900. The method 1900 includes determining the airflow needed 1910 and then to produce the fan speed to attain or approximate the airflow needed, as depicted by reference numeral 1920.

FIG. 20 shows an apparatus 2000 for controlling the power to a device, such as a fan on a furnace, according to an example embodiment. The apparatus 2000 includes a processor 2010, a device 2020 under the control of at least a portion of the processor 2010, and a power source 2030. Communicatively coupled to the processor 2010 is a memory device 2040. The apparatus also includes a computer readable media, such as the memory 2040, that includes instructions for causing the apparatus 2000 to perform a method that includes driving the device with a source of alternating electrical power, and disabling a selected number of cycles of power to the device driven by an alternating current. This is represented in FIG. 20 by an output 2050 of the power source 2030. In this particular example, the output 2050 is shown as a sine wave signal, which can represent either voltage or current output from the power source. The output 2050 includes power on sine cycles, such as waves 2051, 2052, 2054, 2055, and 2057, and power off or disabled cycles, such as sine waves 2053 and 2056. The cycles that are disabled or power off cycles, such as sine waves 2053 and 2056, are represented as dotted sine waves. Although shown, the power (voltage and current) are removed under the direction of the microprocessor 2010 or a portion of the processor 2010 termed the control module 530 (also shown in FIG. 5). In one embodiment, the device is a fan 2420 associated with a furnace. The instruction to disable a selected number of cycles of power (such as disabled sine waves 2053, 2057) to the device includes determining a ratio of power cycles to disable to the total number of power cycles. As shown in FIG. 20, the ratio of disabled sine waves 2053, 2057 to the number of total sine waves 2051, 2052, 2053, 2054, 2055, 2056 is thirty three percent. It should also be recognized that a ratio of 67% power on sine waves to disabled sine waves would describe the same condition, namely that the power sine waves are enabled 67% of the time. Of course, different percentages can be used to produce different device 2020 speeds.

Generally, a number of ratios are implemented and the corresponding or associated speed of the device 2020 is measured. Each entry can be stored in memory 2040 in a table 2042. As shown, in FIG. 20, the table 2042 has a column A and a column B. If the measured parameter is fan speed, the speed is measured for a particular ratio of power on cycles to total cycles or for a particular ratio of power disabled cycles to total cycles. An entry is made on the table 2042 by placing the measured speed under column A and by placing the ratio under column B. This table 2042 can then be referenced when attempting to control the device 2040 to achieve or approximate a difference in a parameter, such as fan speed or volume of air moved over a selected amount of time.

Memory 2040 is a type of computer readable media. Other types of computer readable media can also be used with the memory 2040 or in the absence of the memory 2040. Therefore, in some embodiments, the instructions for causing the apparatus 2000 to perform a method further includes measuring a parameter of the device when all cycles are enabled, measuring the parameter of the device after a selected number of the cycles are disabled, and associating the difference in the parameter with the with the ratio of power cycles to disable to the total number of power cycles. In various embodiments, the instruction to measure a parameter includes measuring a speed of the device, measuring an amount of power used by the device, or measuring a volume of air moved by the device. The apparatus 2000 further includes instructions for causing the apparatus to store a plurality of values of associated differences in the parameter with the with the ratio of power cycles to disable to the total number of power cycles, select the parameter to control, select a desired difference for the selected parameter, and find a difference value near the selected desired difference for the selected parameter, and disable a number of power cycles associated with the parameter.

FIG. 21A shows a method 2100 for driving a device 2040, according to an example embodiment. The method 2100 includes driving a device with a source of alternating electrical power 2102, and disabling a selected number of cycles of power to the device driven by an alternating current 2104. Disabling a selected number of cycles of power 2104 to the device includes dispersing the disabled cycles over a selected amount of time to produce a substantially uniform drop in speed over the selected amount of time. In one embodiment, disabling a selected number of cycles of power 2104 to the device includes determining a ratio of disabled power cycles to the total number of power cycles.

FIG. 21B shows another method 2110 for driving a device 2040, according to an example embodiment. The method 2110 includes measuring a parameter of the device when all cycles are enabled 2112, measuring the parameter of the device after a selected number of the cycles are disabled 2114, and associating the difference in the parameter with the with the ratio of power cycles to disable to the total number of power cycles 2116. In one embodiment, measuring a parameter 2114 includes measuring a speed of the device, or an amount of power used by the device, or a volume of air moved by the device. The method also includes storing a plurality of values of associated differences in the parameter with the with the ratio of power cycles to disable to the total number of power cycles 2118, selecting the parameter to control 2120, and selecting a desired difference for the selected parameter 2122. The method 2110 also includes finding a stored difference value near the selected desired difference for the selected parameter 2124, and disabling a number of power cycles associated with the parameter 2126. In still another embodiment, the method also includes determining a number of enabled cycles of power to the device, and distributing the number of enabled cycles substantially equally over a selected number of cycles.

A furnace includes a combustion chamber 110, a fan or gas handling device for moving air into the combustion chamber 110, and a fan control module 530. The fan control module 530 includes a power source for driving the fan with alternating electrical power, and an apparatus for disabling a selected number of cycles of power to the fan driven by an alternating current. The furnace further includes a sensor 2022 for measuring the speed of the device 2020, such as a fan, and a memory 2140 for storing information relating the fan speed to the selected number of cycles disabled as the fan is driven. In some embodiments, the furnace also includes a processor for determining a ratio of disabled power cycles to the total number of power cycles.

The enabling of power cycles and disabling power cycles on a cycle by cycle basis can also be referred to as cycle dithering. In other words, the power cycles are dithered or moved between an enabled state and a disabled state. The percentage of disabled cycles or the percentage of enabled cycles can be used to determine the number of cycles to be disabled over a selected amount of time. In some embodiments, the number of disabled cycles is placed approximately equally over a selected time or selected number of cycles. As shown in FIG. 20, one in every three cycles is disabled. The approximate equal placement of the disabled cycles allows the device to run more smoothly. In other words, this control method can be implemented with less variation in speed of the device 2040. It should also be noted that this control method is more effective on a device 2040 that has a relatively long ramp up at start time and has an appropriate mass so that the device has rotational momentum that will keep the device rotating even in the presence of a disabled power cycle.

FIG. 22 is a flow diagram of a method 2200 for handling a blocked flue condition, according to an example embodiment. One of the methods for determining whether the flue 470 (as shown in FIG. 4) is blocked to determine if there is a temperature drop detected over time at the temperature sensor 472 associated with the flue 470 (as shown in FIG. 4). The method 2200 is one of several methods that can be implemented by the blocked flue detector module, or flue block module 550 (as shown in FIG. 5). Now turning to FIG. 22, the flue blocked detection and shut-down method 22 is based on thermal history found at the flue 470. The basic idea is to measure the temperature at the flue 470 using the detector or sensor 472. The detector or sensor 472 can be a thermal couple or other temperature sensor. The method 2200 includes taking a sample at a sample time, as depicted by reference numeral 2210. The temperature is typically taken at the flue by sensor 472. The temperature sample is added to memory, as depicted by reference numeral 2212 and a threshold value is calculated or determined, as depicted by reference numeral 2214. Also calculated or determined is a maximum temperature drop, as depicted by reference numeral 2216. Over various sample times, an index operation is performed on the list of the individual temperatures, as depicted by 2218. In some embodiments of the invention, the max temp and threshold temperatures are applied to the two latest temperature samples and in other embodiments the max temp and threshold values are applied to temperature drops at the flue over several sample times. Depending upon the number of sample times that are used, a decision is made at the decision tree 2220. The decision basically is whether or not the particular sample or the sample time is less than the max temp minus the threshold. If minus the threshold is not greater than the sample, then the process described is repeated and another sample is taken at the next sample time. If the sample is less than the max temp minus the threshold, then a blocked flue shutdown is performed, as depicted by reference numeral 2222, and the stove is shutdown, as depicted by reference numeral 2224. The calculation of the max temp minus the threshold results in a minimum temperature at the flue below which indicates a problem with blockage of the flue. In other words, when the flue is blocked, the exhaust gases or hot exhaust gases will not be passing through the flue and the temperature will drop.

FIG. 23 is a flow diagram of a method 2300 for handling a blocked flue condition, according to another example embodiment. The first step is to determine a gas flow rate in the flue associated with the biomass furnace, as depicted by reference numeral 2310. In one embodiment of the invention, the flue 470 is provided with a flow meter 474 for determining the gas flow rate in the flue 470. This measured flow rate is then compared to a second threshold gas flow rate, as depicted by reference numeral 2312. Then the biomass furnace is shut down if the first gas flow rate is less than the threshold gas flow rate, as depicted by reference numeral 2314. In other words, if the flow rate out the flue has dropped below a threshold rate, then the flue is considered to be blocked or on its way to being blocked and the furnace is shut down on the basis of a blocked flue.

It should be noted that in some embodiments the method 2200 can be used. In other embodiments, the method 2300 can be used, and in still further embodiments, a combination of these two embodiments can also be used. In other words, a blocked flue condition can be determined by noting that there is a drop in temperature and also a drop in the gas flow rate.

In another embodiment, a method includes determining a first temperature associated with a flue 470 from a biomass furnace, comparing the first temperature to a second threshold temperature, and shutting down the biomass furnace 100 when the first temperature is less than the threshold temperature. In one embodiment, the threshold temperature can be a range of temperatures. In another embodiment, the threshold temperature is a profile of temperatures. The method can also include determining a first gas flow rate associated with a flue from a biomass furnace, comparing the first gas flow rate to a second threshold gas flow rate, and shutting down the biomass furnace when the first gas flow rate is less than the threshold gas flow rate. The threshold gas flow rate can be a range of gas flow rates, or a profile of gas flow rates.

In still another embodiment, a method includes determining a plurality of temperatures associated with a flue from a biomass furnace over a selected time frame, comparing the plurality of determined temperatures to a stored temperature profile of a plurality of temperatures over a time frame, and shutting down the biomass furnace when the plurality of determined temperatures associated with a flue from a biomass furnace over a selected time frame is similar to the stored temperature profile. The method can also include determining a first gas flow rate associated with a flue from a biomass furnace, comparing the first gas flow rate to a second threshold gas flow rate, and shutting down the biomass furnace when the first gas flow rate is less than the threshold gas flow rate. The method can also include determining a plurality of gas flow rates associated with a flue from a biomass furnace over a selected time frame, comparing the plurality of determined gas flow rates to a stored gas flow rate profile, and shutting down the biomass furnace when the plurality of determined gas flow rates over a selected time frame is similar to the stored gas flow rate profile.

Blocked Flue Module

A system includes a combustion chamber 110, a flue 472 in fluid communication with the combustion chamber 110, a sensor 472 associated with the flue 470, the sensor 472 determining a plurality of temperatures associated with the flue 470 over a selected time frame, and a comparator for comparing the plurality of determined temperatures to a temperature profile. The system also includes a combustion chamber shut down mechanism for shutting down the combustion chamber 110 when the determined plurality of temperatures is similar to the stored temperature profile. The system further includes a memory 4004 (shown in FIG., 26) for storing the determined temperatures and the temperature profile. The temperature profile includes a plurality of temperatures determined during a furnace shutdown. The system also includes a processor. The comparator can be a portion of the processor 4000. The processor 4000 is suitably programmed to compare the plurality of determined temperatures to a temperature profile. The system also includes a gas flow rate measuring apparatus associated with the flue. The comparator which can be a portion of the processor 4000, compares a threshold gas flow rate to a measured gas flow value from the gas flow measuring apparatus. The combustion chamber shutdown mechanism is enabled when the measured gas flow value is less than the threshold gas flow value.

A computer readable medium 2700 has instructions 2710 for causing a computer to perform a method that includes determining a plurality of temperatures associated with a flue from a biomass furnace over a selected time frame, comparing the plurality of determined temperatures to a stored temperature profile of a plurality of temperatures over a time frame, and shutting down the biomass furnace when the plurality of determined temperatures associated with a flue from a biomass furnace over a selected time frame is similar to the stored temperature profile. Determining a plurality of temperatures associated with a flue from a biomass furnace over a selected time frame includes measuring the temperature at a sensor associated with the flue of a furnace. In another embodiment, determining a plurality of temperatures associated with a flue from a biomass furnace over a selected time frame includes measuring a temperature at a plurality of sensors associated with the flue of a furnace. In addition, comparing the plurality of determined temperatures to a stored temperature profile of a plurality of temperatures over a time frame. In one embodiment, the temperature profile is generated by blocking the flue of a furnace, and measuring a plurality of temperatures associated with the flue over a time frame. In one embodiment, the computer readable medium has instructions for causing a computer to perform a method including determining a first gas flow rate associated with a flue from a biomass furnace, comparing the first gas flow rate to a second threshold gas flow rate, and shutting down the biomass furnace when the first gas flow rate is less than the threshold gas flow rate.

FIG. 24 is a screen 2400 of a computer or stove interface, according to an example embodiment. The controller or processor 500 in the furnace contains an interface to connect with a microprocessor, such as a computer. The controller transmits operational data that characterizes the stove condition to the controller or computer. The controller also calls for various measurements of various aspects of the furnace 100. This data is received by the processor and placed in a display such as the screen print 2400 shown in FIG. 24. The display 2400 includes ambient air temperature 2410, exhaust fan speed 2412, a feed rate for the fuel, which is entry 2414. Other entries include an ash content 2416, a convection fan speed 2418, a fuel mixture 2420 and convection fan level 2422. Other conditions that are also shown on the interface 2400 include the state of the igniter 2424, and the state control 2426. Various other measured values, such as for the various thermal couples situated around or in the stove or furnace 100 are shown as four entries carrying the reference numeral 2430. There are also entries for the various exhaust fans in terms of the phase, the speed and the set, as depicted by the reference numeral 2440. Furthermore, there are measurements associated with the feeder wheel, as depicted by reference numeral 2450, as well as the system voltage 2460, the system current 2462, and igniter 1 current 2464, and igniter 2 current 2466, and an air compressor current which is 2468. The various values are received from the stove or from the controller and displayed on a display associated with a computer or processor. It should be noted, that additional measured or determined values can be displayed and that the values shown in this particular embodiment are not necessarily limited.

FIG. 25 is a flow diagram of a method 2500 or receiving and displaying information from a furnace or stove, according to an example embodiment.

Interface—PC to Stove Operation

The method 2500 includes receiving a value from an exhaust fan 2510, displaying the value from the exhaust fan 2512, receiving a value from a fuel feed apparatus 2514, displaying the value from the fuel feed apparatus 2516, receiving a value from a first sensor within a stove 2518, and displaying the value from the first sensor 2520. The method 2500 also includes receiving a value from a second sensor 2522 within a flue in fluid communication with the stove, and displaying the value from the second sensor 2524. The value from the fuel feed apparatus includes a length of time the fuel feed apparatus is enabled. The value from the fuel feed apparatus can also include a length of time the fuel feed apparatus is disabled. The value from the fuel feed apparatus includes a feed cycle time between a first time when the fuel feed apparatus is enabled and a second time when the fuel feed apparatus is enabled. In some embodiments, receiving a value from a first sensor within a stove 2518 includes receiving a value from a thermocouple within a combustion chamber of the stove, and receiving a value from a second sensor 2522 within a flue in fluid communication with the stove includes receiving a value from a thermocouple within the flue of the stove. Receiving a value from an exhaust fan 2510 includes receiving a fan speed value and displaying the value from the exhaust fan 2512 includes displaying the fan speed. The method 2500 can further include calculating a difference between the received fan speed value to a desired fan speed value, and displaying the value from the exhaust fan 2512 includes displaying a percentage difference between the received fan speed and the desired fan speed. In another embodiment, receiving a value from an exhaust fan 2510 includes receiving a an exhaust fan phase value. The method can also include receiving a value from an igniter associated with a stove. Receiving a value from an igniter associated with a stove includes receiving an amount of current being drawn by the igniter. The method 2500 can also include receiving a current value from a stove system, and displaying the current value of the stove system. In still another embodiment, the method also includes receiving a current value from an air compressor associated with a stove system, and displaying the current value from the air compressor. The method can also include comparing value from the exhaust fan apparatus to a desired range of values from the exhaust fan, and indicating a value outside the desired range when displaying the value from the exhaust fan apparatus. The method 2500 can also include comparing value from the second sensor to a desired range of values from the second sensor, and indicating a value outside the desired range when displaying the value from the second sensor.

An article of manufacture includes a computer-readable medium 2700 (see FIG. 27) having stored thereon a data structure. The data structure includes a first field containing data representing a combustion chamber temperature value, and a second field containing data representing an exhaust gas temperature value. The article of manufacture further includes a display for displaying the first field and the second field. In some embodiments, the article of manufacture further includes a third field containing data representing a fuel feed rate value, and a fourth field containing data representing an igniter value. The article of manufacture further includes a display for displaying the first field, the second field, the third field and the fourth field. The article of manufacture, in some embodiments, includes a fifth field containing data representing a fuel type value.

Ash Dump and Timing Module

The ash dump and timing module 560 controls the ash dump and timing process in the stove or furnace. The ash dump and timing process is implemented as a counter which is incremented by an amount time in response to each time fuel is added to the fire. The amount added represents the ash that remains after combustion. Different fuels have different ash amounts, and the effective ash content can change based on the temperature of combustion. For instance, a light ash might fly out of the burn pot at higher heat levels, effectively reducing the ash content.

In the default state, the stove has an ash target of 16,000. Once the ash counter reaches this amount, the ash dump process will be initiated. If the ash content of the fuel is 16 counts per feed, then it will take 1000 feeds to reach the ash dump time. The variable ash dump timing is achieved by adjusting the ash dump target.

The implementation of a fuel profile in the stove provides the flexibility to define a wide range of fuels. However, there may be variations from batch to batch. In this case, a manual adjustment is necessary. In the event that the internal fuel calibration is not quite correct for the fuel that is being used, a control knob was added to the stove or furnace. This is the “Ash Dump Frequency” control. It has a bifurcated scale of ¼× to 1× to 16×. If it is set to ¼x, the dump cycle will take 4 times longer than usual, while if it is set to 16× it will dump 16 time more often than usual. This wide range is meant to encompass the ever wider range of fuels that are being developed.

At the end of the manufacturing process the stove is electrically and mechanically tested to verify basic functionality and assembly. The software in the stove communicates with the software on the PC to perform the various tests. Some tests require the operator to activate or observe parts on the stove, while other tests are automatically performed. In addition to performing these tests at the end of manufacturing, these tests may be selectively performed on select components at a later time to determine if one or more of the select components still exhibits basic functionality. This application incorporates U.S. patent application Ser. No. 10/802,463 and entitled “Burn Pot for Furnace” herein by reference.

FIG. 27 is a display 2700 displaying test results from many of the components included in a biomass furnace 100, according to an example embodiment. Many components and various modules are tested at various times. For example, as shown in FIG. 27, a circulation fan is tested for operation at various levels as depicted by reference number 2710. These are examples of interactive tests which are performed by an operator or user. In addition to interactive tests, there are also automatic tests for the exhaust fan at various power levels, as depicted by reference number 2740, the igniters, as depicted by reference number 2743, and for the feed motor, as depicted by reference number 2747. The automatic tests are conducted under the direction of a microprocessor which tests the components. One time that testing is conducted is at the end of the manufacturing. At the end of the manufacturing a checkout process is conducted, and a report is generated. The report includes the model number of the machine and other identifiers. The test date, production date and serial numbers are also printed out or displayed. Listed below is an example of the information found in a test report.

-   -   Bixby Energy MaxFire Checkout 6.0 Test 10     -   Test Date Tuesday Nov. 7, 2006, 13:56:57     -   Tested By: qa2     -   Version: 03.00.01.0D     -   Checksum: 8fe8     -   Data Format: 05     -   Serial Number: 9828     -   Production Date: 11072006     -   Model: MaxFire 120     -   Fan Levels A: 70, 70, 70, 70, 70, 70, 70, 70     -   Feed Levels A: 100, 100, 100, 100, 100, 100, 100, 100     -   Ash Levels A: 16, 16, 16, 16, 16, 16, 16, 16     -   Startup Adjustments A: 70, 100, 100, 100     -   Ash Dump Adjustments A: 70, 100, 100, 4, 100     -   Fan Speed Adjustments A: 100, 180     -   Fan Levels B: 80, 82, 84, 86, 88, 90, 92, 94     -   Feed Levels B: 85, 85, 85, 85, 85, 85, 85, 85     -   Ash Levels B: 6, 6, 5, 5, 5, 4, 4, 4     -   Startup Adjustments B: 82, 114, 100, 75     -   Ash Dump Adjustments B: 86, 85, 100, 4, 100     -   Fan Speed Adjustments B: 100, 180     -   Status Description Items to check     -   OK 01 Data communication link     -   OK 02 Checksum verified     -   OK 03 Data format matched     -   OK 04 Front panel buttons off     -   OK 05 Front panel ON button     -   OK 06 Front panel OFF button     -   OK 07 Front panel UP button     -   OK 08 Front panel DOWN button     -   OK 09 Front panel LEDs on     -   OK 10 Front panel LEDs off     -   OK 11 Door switch open     -   OK 12 Door switch closed     -   OK 13 Ash drawer switch open     -   OK 14 Ash drawer switch closed     -   NG 15 Hopper door switch open Switch wiring     -   OK 16 Hopper door switch closed     -   OK 17 Plate motor on     -   OK 18 Plate motor off     -   OK 19 Plates in burn position     -   OK 20 Air pump on     -   OK 21 Air pump off     -   OK 22 Convection fan 100%     -   OK 23 Convection fan 50%     -   OK 24 Convection fan off     -   OK 25 Exhaust trim low     -   OK 26 Exhaust trim high     -   OK 27 Exhaust trim detent     -   OK 28 Feed trim low     -   OK 29 Feed trim high     -   OK 30 Feed trim detent     -   OK 31 Ash trim low     -   OK 32 Ash trim high     -   OK 33 Ash trim detent     -   OK 34 Convection trim low     -   OK 35 Convection trim high     -   OK 36 Convection trim detent     -   OK 37 Fuel mix trim high     -   OK 38 Fuel mix trim detent     -   OK 39 Fuel mix trim low     -   OK 40 Thermometer     -   OK 41 Exhaust thermocouple     -   OK 42 Thermostat open     -   OK 43 Thermostat closed     -   OK 44 Exhaust fan off     -   OK 45 Exhaust fan ½ power     -   OK 46 Exhaust fan full power     -   OK 47 ‘1’ side igniter test     -   OK 48 ‘2’ side igniter test     -   OK 49 ‘1’ side igniter check     -   OK 50 ‘2’ side igniter check     -   OK 51 Feed motor/sensor     -   50 Tests OK, 1 Tests failed, 0 Tests not performed

FIG. 28 is another display 2800 that includes the results of diagnostic checks that are conducted during the operation of the furnace 100, according to an example embodiment. A diagnostic device measures the power used by the stove or furnace. In one embodiment, the diagnostic device is a separate component, such as a digital energy meter controller used for power metering applications. One such component is available from Analog Devices of Norwood, Mass., as part number ADE7763. The digital energy meter controller is used to measure the current used by the furnace along with the line voltage to the furnace. The digital energy meter can also be used to measure voltage and current usage by any one device, component or subsystem of the furnace 100. Thus, the digital energy meter can determine if a component is using more power than expected. In addition, the digital energy meter can be used to determine if the furnace system is exceeding the expected current usage. FIG. 28 includes entries 2810, 2812 for displaying the operating characteristics of the system. In the event that the system exceeds the expected current usage 2814, a safe shutdown process in performed. The measurements from the device show up as system voltage 2810 and system current 2812. The system current max 2814 is the calculated maximum allowable current in the running condition of the furnace 100. System current max 2814 is dynamically recalculated each time a device is turned on or off. Other entries, such as 28120 and 2822 show the current usage associated with a first and second igniter. Still another entry 2830 shows the current usage associated with an air compressor of the furnace.

FIG. 29 is a flow diagram for a method 2900, according to an embodiment of the invention. The method 2900 includes receiving a test result value from a component of a biomass furnace 2910, and displaying the test result value from a component of a biomass furnace 2912. The method, in some embodiments, also includes initiating a test of the component or sending a test instruction sequence to the component 2914. In some embodiments, method includes testing the component. In some embodiments, the method also includes receiving a second test result value from the component of a biomass furnace, and displaying the second test result value from the component of a biomass furnace. The method, in some embodiments, further includes receiving a second test result value from an other component of a biomass furnace, and displaying the second test result value from the other component of a biomass furnace. In still another embodiment, the method includes storing a test result value from the component in a memory apparatus at a first time, storing a second test result value from the component in a memory apparatus at a second time, and comparing the test result value and the second test result value.

An article of manufacture includes a computer-readable medium having stored thereon a data structure that has a first field containing data representing a component of a furnace, and that has a second field containing data representing a test result value associated with the component of the furnace. The article of manufacture further includes a display for displaying the first field and the second field. The article of manufacture may also include a third field containing data representing an other component of the furnace, and a fourth field containing data representing a test result value associated with the other component of the furnace. In some embodiments, the article of manufacture includes a third field containing data representing the furnace, and a fourth field containing data representing a test result value associated with the furnace. In one embodiment, the fourth field contains data representing power consumption associated with the furnace. The article of manufacture can also include a display for displaying the first field, the second field, the third field and the fourth field.

A furnace system 100 includes a combustion chamber 110 for burning biomass fuels, a plurality of sensors for sensing a plurality of furnace conditions, and a plurality of components for controlling conditions associated with the furnace system, and a testing apparatus for testing at least one of the plurality of components. The furnace system can also include a processor having instructions for causing the processor to perform a method that includes receiving a first test result value from a component of the furnace system, and displaying the first test result value from the component of the furnace system. The instructions for the furnace system can causing the processor to perform a method further includes a first test for testing the component. The instructions for the furnace system can cause the processor to perform a test of a control module of the furnace system, and display the result or the control module test of the furnace system.

A block diagram of a computer system 4000 that executes programming for performing the above-described methods is shown in FIG. 26, according to an example embodiment. A general computing device in the form of a computer 4010, may include a processing unit 4002, memory 4004, removable storage 4012, and non-removable storage 4014. Memory 4004 may include volatile memory 4006 and non-volatile memory 4008. Computer 4010 may include, or have access to a computing environment that includes, a variety of computer-readable media, such as volatile memory 4006 and non-volatile memory 4008, removable storage 4012 and non-removable storage 4014. Computer storage includes random access memory (RAM), read only memory (ROM), erasable programmable read-only memory (EPROM) & electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD ROM), Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium capable of storing computer-readable instructions. Computer 4010 may include or have access to a computing environment that includes input 4016, output 4018, and a communication connection 4020. The computer may operate in a networked environment using a communication connection to connect to one or more remote computers. The remote computer may include a personal computer (PC), server, router, network PC, a peer device or other common network node, or the like. The communication connection may include a Local Area Network (LAN), a Wide Area Network (WAN) or other networks.

FIG. 27 illustrates a computer readable medium having a set of instructions 2710, according to an example embodiment. Computer-readable instructions 2710 stored on a computer-readable medium 2700 are executable by the processing unit 4002 of the computer 4010. A hard drive, CD-ROM, and RAM are some examples of articles including a computer-readable medium. For example, a computer program 4025 capable of providing a generic technique to perform access control check for data access and/or for doing an operation on one of the servers in a component object model (COM) based system according to the teachings of the present invention may be included on a CD-ROM and loaded from the CD-ROM to a hard drive. The computer-readable instructions allow computer system 4000 to provide generic access controls in a COM based computer network system having multiple users and servers.

It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Accordingly, the invention is intended to embrace all such alternatives, modifications, equivalents and variations as fall within the spirit and broad scope of the appended claims. 

1. An igniter comprising: an insulative body; and a resistive conductor positioned within the insulative body.
 2. The igniter of claim 1 wherein the insulative body is comprised of a ceramic.
 3. The igniter of claim 1 wherein the insulative body is comprised of a non water absorbing material.
 4. The igniter of claim 1 wherein the insulative body includes a tubular portion.
 5. The igniter of claim 1 wherein the insulative body includes a cylinder of substantially non water absorbing material.
 6. The igniter of claim 5 wherein the insulative body includes a tubular portion, the cylinder of substantially non water absorbing material positioned within the tubular portion.
 7. The igniter of claim 6 wherein the tubular portion is made of a substantially non water absorbing material.
 8. The igniter of claim 1 wherein the resistive conductor is positioned substantially around the cylinder.
 9. The igniter of claim 1 wherein the resistive conductor is positioned substantially within the cylinder.
 10. The igniter of claim 1 wherein the resistive conductor is positioned around the cylinder.
 11. A system comprising: a combustion chamber; a burn pot within the combustion chamber; and at least one igniter positioned to ignite fuel within the burn pot, the at least one igniter further comprising: an insulative body; and a resistive conductor positioned within the insulative body.
 12. The system of claim 11 wherein the insulative body of the igniter is comprised of a ceramic.
 13. The system of claim 11 wherein the insulative body of the igniter is comprised of a non water absorbing material.
 14. The system of claim 11 wherein the insulative body of the igniter includes a tubular portion.
 15. The system of claim 11 wherein the insulative body of the igniter includes a cylinder of substantially non water absorbing material.
 16. The system of claim 15 wherein the insulative body of the igniter includes a tubular portion, the cylinder of substantially non water absorbing material positioned within the tubular portion.
 17. The system of claim 16 wherein the tubular portion is made of a substantially non water absorbing material.
 18. The system of claim 11 wherein the resistive conductor of the igniter is positioned substantially around the cylinder of the igniter.
 19. The system of claim 11 wherein the resistive conductor of the igniter is positioned substantially within the cylinder.
 20. The system of claim 11 wherein the resistive conductor of the igniter is positioned around the cylinder of the igniter.
 21. The system of claim 11 further comprising a controller for controlling the at least one igniter.
 22. A system comprising: a combustion chamber; a burn pot within the combustion chamber; a first igniter positioned to ignite fuel within the burn pot; and a second igniter positioned to ignite fuel within the burn pot, at least one of the first igniter or the second igniter further comprising: an insulative body; and a resistive conductor positioned within the insulative body.
 23. The system of claim 22 further comprising a controller for controlling the at least one igniter.
 24. The system of claim 22 further comprising a back up device for igniting the fuel within the burnpot. 